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T. J. Antrobus

Publications and source records attributed to T. J. Antrobus.

4 recordsLinked to original sources
USGS2001

Canopy disturbance patterns in a bottomland hardwood forest in northeast Arkansas, USA

We characterized canopy disturbance patterns in a bottomland hardwood forest and identified linkages to tree species characteristics and interannual flooding patterns. We located 116 newly formed canopy gaps created by 136 gapmakers of 13 species. Over 83% of the gapmakers were snapped or uprooted (i.e., windthrow). The probability of any given gapmaker snapping or uprooting differed among years, species, and elevations. Neither wood properties nor diameter were major factors in determining the probability of snapping versus windthrow. Quercus texana , which had individuals with larger diameters-at-breast height than trees of other dominant species, was the most frequent gapmaker. The effects of elevation and flooding on the probability of snap versus windthrow seem to be tempered or amplified by interspecific rooting habits and tree morphology. Across species, windthrow occurred at lower elevations than snaps, and Q. texana and Q. lyrata showed differences in elevation between the two disturbance types. The total amount of area in newly-formed canopy gaps, as well as gap size, was relatively low compared to estimates for other forests. Our results suggest that natural disturbance patterns in bottomland hardwood forests are complex and are affected by the interactions among forest structure and composition and flooding patterns.

Arkansas↗
USGS2000

Vegetation dynamics

A disturbance can be defined as 'any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment' (Pickett and White 1985). Vegetation dynamics are a function of the temporal and spatial patterns of the disturbance regime. Natural disturbance regimes support the highest biological diversity; therefore, forest management practices that most closely mimic natural disturbances are expected to sustain the highest biological diversity within a given area (Denslow 1980). In southern forested wetlands, flooding is the dominant disturbance factor, thus plant species are usually distributed along a gowing-season flood gradient (Franz and Bassas 1977).

Book chapter↗
USGS2000

Bird community composition

Neotropical migrants are birds that breed in North America and winter primarily in Central and South America. Long-term population studies of birds in the Eastern United States indicated declines of some forest-dwelling birds, many of which winter in the Neotropics (Peterjohn and others 1995). These declines were attributed to loss of wintering and breeding habitat due to deforestation and fragmentation, respectively. Many species of Nearctic migrants--birds that breed in the northern regions of North America and winter in the Southern United States--are also experiencing population declines. Because large areas of undistrubed, older, bottomland hardwood forests oftern contain large numbers of habitat specialists, including forest-interior neotropical migrants and wintering Nearctic migrants, these forests may be critical in maintaining avian diversity. This study had two primary objectivs: (1) to create a baseline data set that can be used as a standard against which other bottomland hardwood forests can be compared, and (2) to establish long-term monitoring stations during both breeding and wintering seasons to discern population trends of avian species using bottomland hardwood forests.

Book chapter↗